US-12620941-B2 - Circuit assembly for generating a constant current

Abstract

A circuit assembly for generating a constant current, the circuit comprising: a resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient, the first and second resistors being configured such that the variability of resistance over temperature of the first resistor and the variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair; and a voltage input connected to the resistor pair and configured to receive an input voltage, the voltage input and the resistor pair configured to generate a current with a zero temperature coefficient.

Inventors

• Bang Li LIANG

Assignees

• SKYWORKS SOLUTIONS, INC.

Dates

Publication Date

20260505

Application Date

20230102

Claims (20)

1. 1 . A circuit assembly for generating a constant current, the circuit assembly comprising: a resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient, the first and second resistors being configured such that a variability of resistance over temperature of the first resistor and a variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair; a voltage input connected to the resistor pair and configured to receive an input voltage, the voltage input and the resistor pair configured to generate a current with a zero temperature coefficient; and a trimming component configured to compensate for a process variation of the resistor pair and including one or more further resistors connected to the input voltage and the resistor pair, the resistance of the one or more resistors being so as to trim the variation in the current produced by the process variation of the resistor pair, the resistance of the one or more resistors set so that one or more bits of a bit value of output current that comprises the variation are trimmed so as to trim the variation in the current produced by the process variation of the resistor pair.
2. 2 . The circuit assembly of claim 1 wherein the variability of resistance over temperature of the first resistor is based on a resistance of the first resistor and the positive temperature coefficient, and the variability of resistance over temperature of the second resistor is based on a resistance of the second resistor and the negative temperature coefficient.
3. 3 . The circuit assembly of claim 2 wherein the resistance and the positive temperature coefficient of the first resistor and the resistance and the negative temperature coefficient of the second resistor are such that the variability of resistance over temperature of the first resistor and the variability of resistance over temperature of the second resistor cancel.
4. 4 . The circuit assembly of claim 3 wherein the resistance of the first resistor and the resistance of the second resistor are chosen such that the positive temperature coefficient of the first resistor is equal in magnitude to the negative temperature coefficient of the second resistor, but opposite in polarity, such that the positive temperature coefficient of the first resistor and the negative temperature coefficient of the second resistor cancel to produce the zero temperature coefficient for the resistor pair.
5. 5 . The circuit assembly of claim 1 wherein the current is generated by the input voltage being applied across the resistor pair so as to be divided by the resistance of the resistor pair.
6. 6 . The circuit assembly of claim 1 further comprising a trimming component configured to compensate for a process variation of the resistor pair.
7. 7 . The circuit assembly of claim 6 wherein the trimming component includes one or more further resistors connected to the input voltage and the resistor pair, the resistance of the one or more resistors being so as to trim the variation in the current produced by the process variation of the resistor pair.
8. 8 . The circuit assembly of claim 7 wherein the resistance of the one or more resistors is set so that one or more bits of a bit value of output current that comprises the variation are trimmed so as to trim the variation in the current produced by the process variation of the resistor pair.
9. 9 . The circuit assembly of claim 1 further comprising one or more current outputs for outputting the current with the zero temperature coefficient.
10. 10 . The circuit assembly of claim 9 further comprising a radio frequency amplification circuit connected to the one or more current outputs and configured to receive the current with the zero temperature coefficient as a bias or reference current.
11. 11 . A circuit assembly for generating a constant current, the circuit assembly comprising: a resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient, the first and second resistors being configured such that a variability of resistance over temperature of the first resistor and a variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair; a voltage input connected to the resistor pair and configured to receive an input voltage, the voltage input and the resistor pair configured to generate a current with a zero temperature coefficient; one or more current outputs for outputting the current with the zero temperature coefficient; and a radio frequency amplification circuit connected to the one or more current outputs and configured to receive the current with the zero temperature coefficient as a bias or reference current, the radio frequency amplification circuit including a radio frequency protection circuit connected to the one or more current outputs and configured to receive the current with the zero temperature coefficient as a bias or reference current.
12. 12 . The circuit assembly of claim 1 further comprising one or more voltage outputs for applying an output voltage set by the current with the zero temperature coefficient.
13. 13 . The circuit assembly of claim 12 further comprising a radio frequency amplification circuit connected to the one or more voltage outputs and configured to receive the output voltage as a bias or reference voltage.
14. 14 . A circuit assembly for generating a constant current, the circuit assembly comprising: a resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient, the first and second resistors being configured such that a variability of resistance over temperature of the first resistor and a variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair; a voltage input connected to the resistor pair and configured to receive an input voltage, the voltage input and the resistor pair configured to generate a current with a zero temperature coefficient; one or more voltage outputs for applying an output voltage set by the current with the zero temperature coefficient; and a radio frequency amplification circuit connected to the one or more voltage outputs and configured to receive the output voltage as a bias or reference voltage, the radio frequency amplification circuit including a radio frequency protection circuit connected to the one or more voltage outputs and configured to receive the output voltage as a bias or reference current.
15. 15 . A radio frequency amplifier system comprising the circuit assembly of claim 1 and a radio frequency amplifier.
16. 16 . The radio frequency amplifier of claim 15 wherein the circuit assembly is configured to provide the generated current as a bias current for the radio frequency amplifier.
17. 17 . A mobile device comprising the circuit assembly of claim 1 , an antenna, and a radio frequency amplifier provided on a die.
18. 18 . The circuit assembly of claim 11 wherein the variability of resistance over temperature of the first resistor is based on a resistance of the first resistor and the positive temperature coefficient, and the variability of resistance over temperature of the second resistor is based on a resistance of the second resistor and the negative temperature coefficient.
19. 19 . The circuit assembly of claim 18 wherein the resistance and the positive temperature coefficient of the first resistor and the resistance and the negative temperature coefficient of the second resistor are such that the variability of resistance over temperature of the first resistor and the variability of resistance over temperature of the second resistor cancel.
20. 20 . The circuit assembly of claim 11 wherein the current is generated by the input voltage being applied across the resistor pair so as to be divided by the resistance of the resistor pair.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. BACKGROUND Field Embodiments of the invention relate to the field of circuit technology for the generation of output current, and more particularly to systems and methods for the generation of constant current for use as reference currents, bias currents and the like. Description of the Related Technology A circuit with a resistor and a diode is commonly used with an input voltage to create a current for use as a bias or reference current, or to provide a bias or reference voltage, that can be used in numerous types of systems including amplifiers, sensors, etc. The circuit can be integrated into these systems or provided separately. SUMMARY In some aspects, the techniques described herein relate to a circuit assembly for generating a constant current, the circuit assembly including: a resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient, the first and second resistors being configured such that a variability of resistance over temperature of the first resistor and a variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair; and a voltage input connected to the resistor pair and configured to receive an input voltage, the voltage input and the resistor pair configured to generate a current with a zero temperature coefficient. In some aspects, the techniques described herein relate to a circuit assembly wherein the variability of resistance over temperature of the first resistor is based on a resistance of the first resistor and the positive temperature coefficient, and the variability of resistance over temperature of the second resistor is based on a resistance of the second resistor and the negative temperature coefficient. In some aspects, the techniques described herein relate to a circuit assembly wherein the resistance and the positive temperature coefficient of the first resistor and the resistance and the negative temperature coefficient of the second resistor are such that the variability of resistance over temperature of the first resistor and the variability of resistance over temperature of the second resistor cancel. In some aspects, the techniques described herein relate to a circuit assembly wherein the resistance of the first resistor and the resistance of the second resistor are chosen such that the positive temperature coefficient of the first resistor is equal in magnitude to the negative temperature coefficient of the second resistor, but opposite in polarity, such that the positive temperature coefficient of the first resistor and the negative temperature coefficient of the second resistor cancel to produce the zero temperature coefficient for the resistor pair. In some aspects, the techniques described herein relate to a circuit assembly wherein the current is generated by the input voltage being applied across the resistor pair so as to be divided by the resistance of the resistor pair. In some aspects, the techniques described herein relate to a circuit assembly further including a trimming component configured to compensate for a process variation of the resistor pair. In some aspects, the techniques described herein relate to a circuit assembly wherein the trimming component includes one or more further resistors connected to the input voltage and the resistor pair, the resistance of the one or more resistors being so as to trim the variation in the current produced by the process variation of the resistor pair. In some aspects, the techniques described herein relate to a circuit assembly wherein the resistance of the one or more resistors is set so that one or more bits of a bit value of output current that includes the variation are trimmed so as to trim the variation in the current produced by the process variation of the resistor pair. In some aspects, the techniques described herein relate to a circuit assembly further including one or more current outputs for outputting the current with the zero temperature coefficient. In some aspects, the techniques described herein relate to a circuit assembly further including a radio frequency amplification circuit connected to the one or more current outputs and configured to receive the current with the zero temperature coefficient as a bias or reference current. In some aspects, the techniques described herein relate to a circuit assembly wherein the radio frequency amplification circuit includes a radio frequency protection circuit connected to the one or more current outputs and configured to receive the current with the zero temperature coefficient as a bias or reference